Process for production of high grade naphthalene and preparation of beta-naphthol from acidic waters therefrom



AQNHELLER April 28, 1959 2,884,463 PROCESS FOR PRODUCTION OF HIGH GRADE NAPHTHALENE AND PREPARATION OF -NAPHTHOL FROM ACIDIC WATERS THEREFROM Filed June 26, 1957 ATTORNEY A. N. HELLl-:R v

April 28, 1959 PROCESS FOR PRODUCTION OF HIGH GRADE NAPHTHALENE AND PREPARATION OF B-NAPHTHOL FROM ACIDIC nWA'IERS THEREFROM 2 Sheets-Sheet 2 Filed June 26, 1957 INVENTOR AUSTIN N.HELLE.R

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United States Patent O PROCESS FOR PRODUCTION OF HIGH GRADE NAPHTHALENE AND PREPARA- TION OF -NAPHTHOL FROM ACIDIC WATERS 4THEREFROM Austin N. Heller, Ramsey, NJ., assignor to Allied Chemical Corporation, New York, N .Y., a corporation of New York Application June 26, 1957, Serial No. 668,085 s claims. (ci. 26o-62s) This invention relates to treating naphthalene and more particularly refers to a new and improved method of refining crude naphthalenes for the production of high grade naphthalene and substantial yamounts of -naphthol.

In early units for the preparation of crude naphthalene from coal tar, tar distillation fractions boiling between 200 C. and 250 C. were chilled, the crystallized naph thalene separated from the oil and then washed with hot Water in centrifugals or hot pressed in hydraulic presses to remove adhering oil. More recent practice has been to collectla coal tar fraction boiling between 200 C. and 250 C., wash with aqueous caustic, and distill to produce naphthalene having a 73 C. freezing point. This naphthalene is crystallized from aqueous caustic to yield whizzed naphthalene having a 78 C. freezing point. In `some modern units the coal tar fraction boiling between 200 C. and 250 C. is washed with aqueous caustic and fractionated in Ian efficient column to yield distilled naphthalene having a 78 C. freezing point. To produce refined naphthalene, the 78" C. Ifreezing point naphthalene is treated several times 4at about 90 C. with concentrated sulfuric acid, washed repeatedly with water, neutralized with aqueous caustic and finally redistilled to yield refined naphthalene with a 79.6 C. minimum freezing point.

The conventional method for producing refined naphthalene from crude naphthalene is complex and a somewhat wasteful process. Acid sludges are produced in 4acid-treating crude naphthalene and these sludges are conventionally discarded although they may conceivably be incinerated to recover their H2804 values. Sulfonic acids present in the sludge are entirely destroyed by either procedure. Besides the loss o f acid sludges in conventional naphthalene refining, an equally undesirable processing Waste results from discharging the acidic rinse water 4and soda sludges. These wash Waters `are too dilute for profitable recovery and too copious to permit economical neutralization. Combined wash waters and lacid sludges, due to their high acidity and organic constituents may cause water pollution problems if discharged into a receiving stream.

Furthermore, the refined naphthalene conventionally produced is not of `especially high quality, usually barely meeting the freezing point specification of 79.6 C. To improve the quality of such refined naphthalene requires special expensive treatment and consequently the cost of high grade naphthalene of 79.9 C.80.0 C. freezing point commands 'an appreciably higher market price.

An object of the present invention is to provide a method of" refining naphthalene under conditions eliminating certain conventionally encountered wastes and producing sidestreams amenable to conversion to -naphthol.

Another object is to provide ya method for producing refined naphthalene of consistently high quality, with high (79.9 C. minimum) RP., exceptionally low sulfur coutent, improved visual appearance and color` stability and superior heat stability.

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A further object is to provide a method for refining naphthalene involving no acid sludges.

A still further object is to provide a method of refining naphthalene at high temperatures and of treating cer; tain aqueous wastes resulting from such refining opera;V tions so as to obtain economically attractive yields of -naphthol while substantially eliminating Water pollution normally associated with such refining. Other ob` jects and advantages will be apparent from the accom-V panying drawing and following description.

In accordance with the present invention, naphthalene of exceptionally high purity (79.9 C.-80.0 C. minimum freezing point) may be obtained by mixing crude naphthalene with 10-25, preferably 14-20, parts by weight of crude naphthalene of concentrated sulfuric acid containing 90-l00%, preferably 93-96%, H2SO4 at a temperature of 15G-170 C., preferably 155-165 C., and continuing the mixing of the crude naphthalene and sulfuric acid to for-m essentially a single phase, i.e., a hornogeneous mixture that does not separate into layers, there' after adding water to the single phase mixture at a temperature of S0l00 C., preferably 85-95 C., to form two phases, an 'aqueous phase termed acid waters containing naphthalene sulfonic acids and impurities in the form of water-soluble sul-fonated polymers and a naphthalene phase, withdrawing the laqueous phase, washing the thus sepa-rated naphthalene phase with a dilute aqueous caustic solution, withdrawing the aqueous caustic so-` lution after contact With the naphthalene, and fractionally distilling the thus treated naphthalene and recovering las distillate a high quality naphthalene of exceptionally 'low sulfur content, good color stability and superior heat stability. K

In another embodiment of the invention, the single phase mixture of crude naphthalene and sulfuric acid is countercurrerrtly washed with a dilute aqueous solution of sodium sulfate at -a temperature slightly above C., at which temperature visible crystals of naphthalene bgin to form. The fine naphthalene crystals separate out as an upper layer due to the higher density of the aqueous solution of sodium sulfate land the separated naphthalene crystals are washed With an aqueous caustic solution and the washed naphthalene fractionally distilled to produce refined naphthalene of high quality.

The present invention further permits increasing the 'available supply of -aphthol, which is an intermediate for the industrial manufacture of dyes and pharmaceuticals, from lthe acid waters and caustic wash, normally waste by-products resulting from production of refined naphthalene as described above. -Naphthol is also employed for preparing an important rubber antioxidant (N-phenyl-Z-naphthylamine) and is used medicinally as a parasiticide and anthelmintic'. The normal process for manufacturing -naphthol requires use of relatively costly refined naphthalene of 79.6 C. freezing point While the present invention utilizes readily available by-product wastes from refining crude naphthalene having 78 C. freezing point.

Accordingly, acid water, produced as lay-product in the purification of crude naphthalene in accordance with the present invention, may be converted into additional yields of naphthalene and -naphthol by first concentrating the acid water, thereafter, if desired, passing steam, in 4direct contact with the concentrated acid water at a temperature of ISO- C. to thereby convert naphthalene-l-sulfonic acid contained in relatively small amount in the acid water to naphthalene which latter is removed by vaporization and recovered. The residual Waste water containing a substantial amount of naphthalene-2-sulfonic acid is neutralized with an alkali water, aqueous caustic produced as a by-product in the acid purification of naphthalene, and a mixture of sodium sl- 290-350" C., `thereby effecting desulfonation of the so dium` naphthalene-Z-sulfonate. The melt is dilutedwith water and then acidied with the sulfur dioxidegasy re-v leased from the reaction. As a result of this acidication, there` is'formed naphtholwhich separates as one layer and an aqueous-solution of sodium sulfate and sodium sulte which may be recycled in the process for neutral#V izing lthe naphthalene-Z-sulfonic acid and produce the sodium naphthalene-Z-sulfonate. The -naphthol may then bel purified by washing-with water, dehydration,

residue-freeing Yand/or fractionation.

carrying out the present invention. Figure 2 illustrates another and alternate embodiment of the present invention. 4

. Referring to-Figure l, crude naphthalene (77.7`78.70 C. v'freezing point) is delivered through line 1 to reaction vessel 2 provided with stirrer 3. Concentrated sulfuric acidin an .amount of l-25 parts by weight'of crude naphthalene is introduced through `line 4 into reaction vessel 2 and the mixture agitatedat a temperatureof 15G-170 C. to effect intimate contact between the crude naphthalene and sulfuric acid and to form a homogeneous mass, i.e. a. single phase with noseparation of acid sludges. Ordinarily, vformation of a single phase with reaction'of thel acid on the impurities in the crude naphthalene will be completed in about 1/2-2 hours. .The singlevphase naphthalene-H2SO4 mixture is transferred through-line 5) to water washing chamber 6 wherein the single phase material at a temperature of 80-100" C. is admixed with water, usually an amount of 25-50% water by volume of the *naphthalene charged will be adequate, `entering through line 71and `themixture upon standing separates into a bottom aqueous layer termed acid Water containing the naphthalene sulfonic acidsy and impurities and an' uppernaphthalene layer from which the impurities have been removed. The acid water is discharged from the bottom of chamber 6 through line 8. The naphthalene layer is delivered through -line 9 toy neutralizer 11 into,l

which an aqueous solution ofk sodium hydroxide is introduced through line 12 contacted with the naphthalene and `the mixture thereafter permitted to settle into a lower aqueous caustic layer which is discharged throughline 13y and an upper naphthalene layer. The treated naphthalene from neutralizer 11 is sent through' line 14 into fractionating tower 15 wherein naphthalene is vaporizedand taken overhead through line y16, condensed in condenser 17, and then delivered through line y18 into receiver 19. The distilled naphthalene in receiver 19 will have a 79.9-80.0 C. minimum freezing point. -The residue consisting principally of a small amount of polymers collecting in the bottom of fractionating tower 1S may be discharged through line 21.

Acid water fromv water washing chamber 6 is delivered through line 8 to evaporator 22 wherein the acid waters are concentrated. Concentrated acid water from evaporator 22 `is directed through line 23 to desulfonatorf'24 wherein the acidrwaters are maintained ata temperature of 150170 C. and steam may be introduced through line 2,5 1n direct contact with the concentrated acid water to convert naphthalene-l-sulfonic acid to naphthalene.

Thethus liberated naphthalene is released as vapors from' the top of desulfonator 24 through line 26 and recovered. Residual acid Water containing naphthalene-Z-sulfonic acid yis transferred via line 27 to neutralizer 28 where it may be neutralized with alkali water from chamber 11 owing down through lines 13 and 29 into neutralizer 28. A mixture of sodium sulfate and sodium sulte may also be introduced through lines 31 and 29 into neutralizer 28. The effect of neutralization is to form sodium naphthalene-Z-sulfonate whichis sentvia lline 32 to fusion ceases `kettle 33 wherein itis y through line 34 at a temperature of about 305 C. SO2 gas formed by reactionof sodium `suliite ywith naphthalene-Z-sulfonicacid is vented from rneutralizer 28 through f line 35.` The resulting melt, sodium. -naphtholate, is `sent from fusion kettle 33 through line 36 todilution *tank 37 whereiny itais drowned or diluted with water or water/containing sodium sulfate and sodium sulte enter- Figure 1 diagrammatically illustrates onekm'ethod ofy ing through line 38. After drowning the melt, the aqueous solution containing sodium sulfate and sodium sulte is `separated from the -sodium -naphtholate ina conventional manner, e.g. by iiltration or centrifuging and discharged through line 39` to drier 41 and the dried sodium rthrough lines 31' and29 to neutralizer 28. The sodium -naphtholate is sent fromtank 37 through line 44 to springing chamber' 45 wherein the sodium ,S-naphtholate is aciditied with sulfur dioxide `liberated in neutralizer 2S and entering springing `chamber 45 through line 35. Water containing sodium sulfate and sodium sulite en-` ters through line 46. -Naphthol and sodium sulte are transferred from springing chamber `45 via line 47 to washingchamber '48-wherein the fnaphthol is washed with water entering through line 4.9., The wash water containingsodium sulflt'eandjsodium sulfate is withdrawn from chamber 48 through line 51 and lrecycled` through` 41E-.is delivered through line 52 to dehydrator 53 for ree` moval of .water'and thencethroughline-54 to fractionatorfvk from the top of which Vthrough line 56 -naphthol"` .vapors are removed, condensed andy recovered. TheA minor amount of fractionator bottoms are dischargedl through line 57` `and maybe incinerated for recovery of fuel value or sent to a dump. .v

. Equations representing the reactions of the acid Water to -naphthol as described above ^`are presented below:

' extraction eiciency may be achieved in a solid-liquid extractedwith a solvent at temperatures slightly abovev the crystallization point of the pure material.

fused with NaOH introduced f in they conversion other and alternate embodiment of the present inev ventionemploying continuous operation is schematicallyv presented 'in Figure 2. .In this application of the presentyinvention, advantageistaken of theifact` `that .a higherY 't Referring to Figure 2 crude naphthalene-(78 C. freeze ingpoint) is introducedv through line 61 into agitator` tower 6,2l which is a tall narrow cylinder provided with multiple agitator blades 63 connected to a single rotary Shaftk 6,4 driven by motor 60. In tower 62 the crude naphthalene is contacted concurrently at about 165 C. with about l-25 parts of concentrated sulfuric acid entering through line 65. The mixture of crude naphthalene and sulfuric acid discharges in single phase from the top of cylinder 62 through line 66 into the bottom of tower 67, which is also a tall narrow cylinder provided with agitator blades 68 fastened to a single shaft 69. Shaft 69 is ro'- tated by motor 71 actuated by cycle-control device 72 which turns motor 7l on and off at predetermined time intervals. In tower 67 the naphthalene entering through line 66 is countercurrently Washed with a dilute aqueous solution of sodium sulfate (sodium sulfate, which may be obtained from the drowning step in the -naphthol manufacture, is used to increase the density of the water phase) at temperature slightly above 80 C. The intervals device 72 stops the agitation, the contents, of the tower are allowed to settle and purified naphthalene crystals are discharged from the top of tower 67 through line 73 to the bottom of tower 74, also a tall narrow cylinder provided with agitator blades 75 fastened to a single rotary shafty 76 driven by motor 77. In tower 74 the water washed naphthalene at a temperature of about 90 C. is countercurrently treated with a 10% aqueous solution of sodium hydroxide entering through line 78. charging from the bottom of tower 67 through line 79 may be converted to naphthol in a manuerdescribed Figure 1. Alkali water discharged from the bottom of tower 74 through line 81 may also be utilized in the conversion of the acid water to -naphthol. The treated naphthalene is discharged from tower 74 through line 82 and fractionated to produce pure naphthalene of 79.9-80.0 C. minimum freezing point.

, vIn additionto an increase in yield of products from crude naphthalene by the process of the present inventionv as compared to conventional processing methods, a.` particular Vadvantage lof the present invention isl the production at minimum cost of an especially high quality refined naphthalene (79.9 C.80 C. freezing point). While present -commercial practice dictates that refined naphthalene should have a freezing point of 79.6- C. or higher, the product is rarely significantly above the minimum value. To make pure naphthalene of 80.0 C.- freezing point it has been conventional practice to refine 79.6 C. freezing point naphthalene with metallic sodium or sublime low sulfur content (0.1% by Weight sulfur) lnaphthalene in large shallow iron tanks at about 150 C. A realization of the cost of these operations may be had from the fact that sublimed naphthalene flakes generally command about four cents a pound price advantage over 79.6 C. freezing point rened naphthalene. Furthermore, if the naphthalene to be sublimed contains approximately 0.25% sulfur (as is common for technical 79.6 C. freezing point naphthalene), other supplemental purification must be used. Generally this is done by treating the molten naphthalene with about 1% metallic sodium, followed by vacuum distillation.

While refined naphthalene is occasionally obtained with a very low sulfur, tar base, or tarry body content, the yreliable production of such high quality naphthalene by conventional means is quite uncertain. While the exact causes for the superiority of some batches over others are not positively known, it appears to be in general a function of the eXpertness with which the sulfuric acid sludges are separated from the naphthalene before water washing is begun.

Since the present invention involves no acid sludges, the refined naphthalenevis consistently of high quality and possesses the following advantages: i "Ca') Exceptionally low sulfur content (approximating Acid water dis-- descansa, rather than 0.21%. .forecnventcnally te.,

fined naphthalene).

('b) Improved visual appearance and color stability (samples have retained a pure white color when exposed to light while conventionally refined naphthalene made from the same crude naphthalene darkened).

As a further illustration, a molten sample of refined naphthalene prepared according to the present invention' was tested for color stability by insertion of a 100. ml. Nessler tube, filled to the mark, into a' heating block at 200 to 205 C. A conventionally refined sample made from the same crude naphthalene was similarly tested. The color of the samples was ascertained visually at intervals in a colorimeter by comparison with standards. The method of comparison was Test Method I-10 described as Color, B-Series Color Standards, Serial No. 84H2l (December 1954) in The Manual of Barrett Test Methods, published by Barrett Division, Allied Chemical and Dye Corp., 40 Rector Street, New York city. The result-V ing data are shown in the table below:

COMPARISON OF COLOR 'STABILITIES Color After Heating Type of N aphthalene The above data clearly show the superior stability at elevated temperatures of refined naphthalene prepared according to the present invention over conventionally refined naphthalene. This superior stability is undoubt: edly dueto more complete removal of impurities from the crude naphthalene by the process ofthe present invention. v v i The nature of the impurities, ordinarily present in crude naphthalene before sulforlation,l is determined by the method employed to obtain 'the naphthalene from coal tar. Thus a 78 C. freezing point whizzed naphthalene obtained b y crystallization of 73 C. freezing point naphthalene from aqueous caustic will ordinarly contain 1 to 2% thianaphthene and 2 to 4% of the other impurities comprising substituted furanes, methylnaphthalenes, dimethylnaphthalenes, and traces of tar acids and tar bases. A 78 C. freezing point naphthalene produced directly by fractional distillation of caustic washed coal tar dis'.- tillate will ordinarily contain 3 to 4% thianaphthene, and l to 2% other impurities, chiefly tar acids. Treatment under conditions in accordance with the present invention effects complete sulfonation and polymerization ofy the large amount of thianaphthene present and thereby purifies the 78 C. freezing point distilled naphthalene. No acid sludge is formed, and upon washing withwater and aqueous caustic, these sulfonated polymers are dissolved in the aqueous phase along with a somewhat larger amount of naphthalene sulfonic acids resulting from sul fonation of a portion of the naphthalene. Upon preparation of -naphthol from the by-product acidic Waters, the impurities are recovered as vstill residue in the -naphthol distillation.

The following examples illustrate the present invention.

EXAMPLE 1 A 50 liter 3-neck round bottomvflask equipped with electrical heaters, mechanical stirrer,4 thermometer well and addition funnel was fitted with a hot`water condenser (about 80 C.) set at total reflux and topped by a cold 'Water condenser also set at total reflux and equipped at its exit with gas scrubbing equipment. Into the ask was poured 30,000 g. of melted crude distilled naphthalene (RP. 78.0 C.). The naphthalene was heated with agita,- tlon to C. and 4,800 g. (1,6% by weight of charged naphthalene) of conc. sulfuric acid was added4 rapidly through the addition funnel. The mixture was agitated at 165 C. for 1.75 hours while the sulfur dioxide gas was allowed to pass through the condensers to the gas scrub` bing equipment. Entrained naphthalene was separated from the gas stream by condensation and returned to the reaction flask. Water was condensed and removed (105 g.) from the gas stream as needed to maintain reaction temperature.

After completed `reaction time, the single phase mixture was cooled to 90 C. and 8,910 g. of hot water was added. The mixture was agitated for 0.5 hr. at 90 C. and then allowed to settle for 0.75 hr. at 90 C. At the end of this period the lower phase acid water was siphoned ot and allowed to cool. The acid water was filtered, the cake heated and the melted material from this cake returned to the reaction flask. The 'remaining solids (463 g.) vcontained 45.8% -naphthalene sulfonic acid. The acid water ltrate weighed 16,844 g. and had the following composition:

Total acidity as HZSO., (percent) 14.6 Free H2SO4 (unutilized) (percent) 4.9 -Naphthalene sulfonic acid (percent) 26.1 Specific gravity 1.185

of this'period the lower aqueous phase was drawn off,

allowed to cool to room ftemperature, ltered and the iilter'cake sucked dry. The dried cake had the following characteristics weight f g .328.0 Sodium -naphthalene sulfonate percent-- 45.5

'alkali w'ater-l'iltrate (2753 g.) had the following composition: v 'rotar alkalinity as NaOH (percent) 5.3

Free sulfate as Na3S04 (percent) 0.63 Sodium -naphthalene sulfonate (percent) None Specificgravity 1.094

The washed-purified naphthalene was siphoned from the reaction askandweighed 25,497 g.

Aportion ofthe washed-purified naphthalene was` dried and 400 g. of the dried material was subjected to fractional distillation using a 36" X 1"'Stedm`an column, 87 pressureand a 5:1 reflux ratio. Of the charged material, 90.25 was obtained as distillate and 86.68% met or surpassed specifications. The overall yield of crude yto rcined "naphthalene was 73 .68%

Eighteen hundred g. of the acid water from this run was placed in a -3 liter 3-neck round bottom ilask equipped with heating mantle, thermometer well and condenser set for distillation. The solution was concentrated until the pot temperature reached 165 and was then blown with superheated steam at 16S-175 C. for 25 minutes. From the vaqueous distillate 100.6 g. of naphthalene (RP. 77.5 C.) was isolated by filtration. The steam-blown, concentrated acid water was allowed to cool to 100 C. and was then poured into 1500 ml. of water. The aqueous solu tion was heated almost to boiling and 1450 ml. of 18% sodium sulte solution and 250 ml. of 16% sodium sulfite solution were. added. .Excess sulfur dioxide was boiled off and ther r40%y sodium hydroxide solution was added to pH 8. Thesolution was allowed to cool slowly to room temperature andthe resulting slurry ltered. The

i asstra held at 305 C. for 0.5 hour. The reaction mixture was then cooled and dissolved in 1300 ml. water. The aque freed -naphthol obtained weighed 46.6 g, (77.7% based on mass charged to the fusion pot) and had the following characteristics:

Mr. C-. 1219-1225' Percent a-naphthol The residue in the Stm por weighed .11.6 g.

' EXAMPLE 2 Part I.-Naphthalene purification Two hundred and fty pounds of crushed 78 C. distilled naphthalene were charged into a 50 gallon, jacketed, oil-heated, glass-lined and agitated kettle. Charge was heated to 165 C., agitation started when mass became fluid. Forty pounds (16% of thenaphthalene charged) of 66 B, H2804 were rapidly added over a 15-30 minute period. Reaction was maintained after acid addition for 1% hours at a temperature of 165 C. in single phase.

Reactionrvapors 4were taken off through a hot 'water jacketed, glass vapor line, and condensed in a glass lined condenser; Resultant' condensate was collected for recovery of solidied naphthalene.

Reaction mass was then cooled to C. With agita- `tion continuing, pounds (40% of naphthalene charged) of hot (90 C.) water was added. Mixing was continued for one hour after addition, and then thebatch was settled' for one hour, during which time the temperature was maintained at 90 C. to effect phase separation, the lower acid water was drawn olf to a stainless steel container and allowed to cool for further recovery of naphthalene. Final acid water (171 pounds) was stored in glass carboys for fI-naphthol processing. Acid analyses summarized as follows:

- Percent ILEI-NSA 21.4 Free SO4= as H2804 4.1 Total acidity as H2504 l11.8

a. Percent of naphthalene Acharged that was distilled 95.9 b. Percent of naphthalene charged as 79.9 or better naphthalene 71.8 c. Percent of naphthalene charged as 79.65 or better naphthalene 93.7

Overall process yield, i.e. from 78 distilled naphthalene to refined naphthalene, for production of 79.6 relined naphthalene equates to 78.0%.

Part 11.-13-Naphthol recovery A.. CONCENTRATION AND HYDROLYSIS One Ihundred sixtynine pounds of dilute acid water were charged into a 50 gallon, jacketed, oil-heated, glassasses@ lined and agitated kettle. The acidwater hadl the fol W inganalysis.;` 1

Charge was heated to 165 C. to elie'ct desired concentration; condensate was collected torecover solidified naphthalene resultingv from decomposition of naphthalene sulfonic acid and distillation of dissolved naphthalene (4.9 pounds as -NSA). Resultant concentrated acid water (57.3 pounds) had the following analysis:

- Percent -NSA n v 42.7 Free SO4= as H2804 12.6 Total acidity as H2S04 29.4

This'l concentration procedurey resulted in an 84.0% actual recovery of ,Ki-NSA through this step. This concentrate was drained into stainless steel trays and allowed to' harden (M.P. 90- -r95 C.).

B. NEUTRALIZATION AND'EVAPORATION- Two 5 pound batches of the resultant concentrated acid water were charged to a 2% gallon steam jacketedl nickel Baker-Perkins Sigma-Arm Mixer. Mass was heated to 90-95" C. to melt the batch. Neutralization was carried out by the slow addition of an l18% solution of sodium sulfite until Congo redtest paper no longer turned blue.

Care lwas exercised t-o' prevent excessive foaming; tem f Percent Water 14.5 NaNS 37.6

Recovery of -NSA, corrected for handling losses, over this step was 94.0%.

C. FUSION, SPRINGING, FILTRATION, AND DISTILLA- TION Six pounds of 100% sodium hydroxide was then charged to a 2 gallon, iron, direct tired agitated fusion pot. Caustic was melted by heatingv pot to 305 C., 10.69 pounds of the neutralized mass from the preceding step were then slowly added to the molten caustic at such a rate as to maintain the temperature between 290- 310 C. Molar ratio `of caustic to NaNS was 8.6; or on the basis of total dry salts as charged, it was 3.23. The fusion mass was then held at 305 C. for 3Q hour after the addition of salt was completed. The mass (15.87 pounds) was then cooled to room temperature and transferred to a stainless tray.

Water (47.6 pounds) and the fusion mass (15.87 pounds) were then charged at-a 3:1 weight ratio to a 10 gallon stainless steel steam jacketed and agitated kettle. The mixture was then heated to 95 C. with agitation. Sulfur dioxide l(4.88 pounds) was then buzbbled through the mass from the bottom outlet valve until "Brom Thymol Blue test paper remained-yellow. The contents (65.1 pounds) were then cooled slowly to room temperature and filtered ona Nutsche type lter. Resultant cake (crude -naphthol) was then-washed with water; final weight was 6.31 pounds having 51.1% volatiles at 60 C.

p `An aliquot of the lter cake was then dried in the laboratory at 60 C. This equated to 3 .09 pounds of diy cake having 63.2% -naphthol- *based onfnal dis I rvil() anni@ with 2.1% @.-naphfhoi in. :hes-named.. .The dry cake aliquotj .was then distilled in asix-ballgSnyder column with internal reliux for rectification.

Overall yield on -NSA for the fusion, springing and distillation steps was 77.3%. This results in a 72.5% yield from the concentrated acid water.

EXAMPLE 3 Part 1.--Naphthalene purification.

Two hundred and fty pounds of crushed 78 C., dis-v tillednaphthalene were charged into a 50 gallon, jacketed, oil-heated, glass-lined and agitated kettle. Chargewas heated to 165 C.; agitation started whenmass became. fluid. Forty pounds (16% of the naphthalene charged) or` 95.5-96.5% C.P. sulfuric acid were rapidly added over a 15'30 minute-period. Reaction wasl maintained after acid addition for 1% hours at a temperature of 165 C.

Reaction vapors were taken o through a hot. water; jacketed., glass vapor line, and condensed infa glass: lined condenser. Reslultant condensate was collected for recovery of solidilied naphthalene. p Reaction mass was then cooledV to C. With agita tion continuing, pounds (40% of naphthalene charged) of hot (90 C.) water was added. Mixing Was co-ntinued for one hour after addition, and then-the batch was settled for one hour., during which time the temperature was maintained at 90 C.` to etect. phase separation, the lower acid water was drawn off to a stainless steel container and allowed to cool for further recovery of naphthalene. Final acid water .(181.9 pounds) was stored in glass carboys for /-naphthol processing. Acid yanalyses summarized as followsz.

Percent NsA 17.3 Free S01,= as H2SO4 3.1 Total acidity as H2504 12.3 The water washed naphthalene was then washed 4and agitated with 25 pounds (10% of naphthalene charged) of 10% caustic soda for one hour at 90 C. This wasv followed at lthe same temperature with one hour of settling. Finallyv the caustic wash `(9.2% NaOH) drawn o the bottom and collected for cooling to recover additional naphthalene. This alkali wash water (19.8 pounds) was discharged.

A sample of the resultant washed-purified naphthalene (201.5 pounds) was distilled in a 1"X36' laboratory Overall process yield, i.e. `from 78 distilled naphthalene to refined naphthalene, for production of 79.6 refined naphthalene equates to 77.3

Part II.-naphthol recovery A. CONCENTRATION AND HYDROLYSIS One hundred 'sixty-tive pounds of dilute acid .wat-,t were' charged into the 50 gallon, jacketed, oil-heated,

glass-lined and agitated kettle. This acid water had the following analysis:

Percent -NSA 16.2 Free S04: as H2804 f4.9.

Toni acidity .fis/H2504 --.14ga

"Charge was heated to 165 C. to eEect desired concentration; condensate was collected to recover solidilied naphthalene resulting from decomposition of naphthalene sulfonic acid and distillation of dissolved naphthalene (6.5 pounds as -NSA). Resultant concentrated acid Water (69 pounds) had the following analysis:

Percent -NSA v 34.2 Free SO4= as HZSO., 14.3 Total acidity as H2804 35.2

This concentration procedure resulted in an 88.4% actual recovery of -NSA through this step. The concentrate was then drained from the kettle into stainless steel trays and allowed to harden (M.P. 90-95 C.).

B. NEUTRALIZATION AND EVAPORATON 'A-"iifteen pound batch of lblended concentrated acid water resulting from concentration as described above, and from an additional steam-blowing to eiect hydrolysis of a-naphthol was charged to a gallon stainless steel jacketed and agitated kettle. Mass was heated to 90-'95 C. to melt the batch. Neutralization was carried out by the slow addition of an 18% solution of sodium suliite A Pounds Charge 15 -NSA in charge 6.47 18 sodium sulte solution 37 30% sodium hydroxide solution 2 Resultant Vmass was discharged onto trays and dehydrated in a tray drier for 44y hours to a moisture content of 0.8%. Dried material amounted to 18.4 pounds containing 33.8% NaNS.

Recovery of ,t3-NSA over this step was 87.0%.

C. FUSION, SP-.INGING,'FIITRATION. AND DISTILLA- Y TION ` Eleven pounds of 100% potassium hydroxide was then charged to a 2 gallon, iron, direct tired, agitated fusion pot. Caustic potash was melted by heating pot to 310 C. Fifteen pounds of neutralized mass from the preceding step were then slowly added to the molten caustic potash at such a rate as to maintain the temperature between 29o-310 C. Molar ratio of KOH to NaNS was 9.0; or on the basis of total, dry salts as charged, it was 3.01. The fusion mass was then held `at 310 C. for 1/2 hour after the addition of salt was completed. The mass (24.44 pounds) was then cooled to room temperature and transferred to a stainless tray.

Water (73.2 pounds) and the fusion mass (24.44 pounds) were then charged at a 3:1 weight ratio to a 10 gallon stainless steel, steam jacketed and agitated kettle. The mixture was heated to 95 C., with agitation. Sulfur dioxide (6.44 pounds) was then bubbled through the mass from the bottom outlet valve until Brom Thymol Blue test paper remained yellow. The contents (101.6

pounds) were then cooled slowly to room temperature` and iilteredr on a Nutsche typelter. Resultant cake (crude -naphthol) was then washed with water; nal Weight was 14.0 pounds having 66.9% volatiles at 60 C.' An aliquot of the ilter cake was then dried in the laboratory at 60 C.` The resultant equated the cake (dried) to 4.64 pounds having 53.2% -naphthol =based on vfinal distillation, with 0.54% -naphthol in the naphthol. The dry cake aliquot was then distilled in a six .ball Snyder column with internal redux for recti- Overall yield in -NSA for the fusion, springing; and distillation steps was 78.3%. This'res'ults in a 68.0% yield from the concentrated acid Water.

EXAMPLE 4 Part I.-Naphthalene purification Two hundred and fty pounds of crushed 78 distilled `naphthalene were charged -into a 50 gallon, jacketed, oil

heated, glasslined and agitated kettle. Charge was heated to 165 C.; agitation started when mass became fluid. Forty pounds, (16% 'of the naphthalene charged) of 66 B. sulfuric acid were rapidly .added over a 15-30 minute period. Reaction was maintained after acid addition for 1% hours at a temperature of 165 C.

y Reaction vapors were taken 0E through `a hot water jacketed, glass vapor line, and condensed in a glass-lined condenser. Resultant condensate was collected for re covery of solidiled naphthalene.

Reaction mass was then cooled to C. With agitation Continuing, pounds (40% of naphthalene charged) of hot (901 C.) water was added. Mixing was continued for one hour after addition, and then the batch was settled for one hour, during which time the temperature was maintained at 90 C.

A phase separation was kthen made. The lower acid water was drawn olf to a stainless steel container and `allowed to cool for further recovery of naphthalene.

. f Percent -NSA 17.3 Free S04= as H2SO4 3.1 Total acidity as H2804 12.3

The water washed naphthalene was` then washed and agitated with 25 pounds (10% of naphthalene charged) of 10% caustic soda for one hour at 90 C. This was followed at the same temperature with one hour of settling. Finally, kvthe caustic washU (9.2% NaOH) was drawn off the bottom and collected 'for cooling to recover additional naphthalene.A g This alkali wash water (19.8 pounds) was discharged.

A sample of the resultant `wash-puritied naphthalene (201.5 pounds),' was distilled ina 1"x 36" laboratory Stedman column. These results summarize as follows:

a. Percent `ol. naphthalene `charged that was distilled b. 'Percent of naphthalene charged as 79.9 or better naphthalene y c. Percent of naphthalene charged as 79.8 or better naphthalene Overall process yield, i.e., from 78 naphthalene to refined naphthalene, for the production of 79.6` refined naphthalene equates to 77.3%.

Part IL-'-Nqphthol recovery A. CONCENTRATION One hundred and sixty-nine pounds of dilute acid water.

were charged into `-the 50 gallon, jacketed, oil-heated, glass-lined and agitated kettle. This acid water had the Charge was heatedto .165 C. to elect desired concentration; condensate was collected to recover solidified naphthalene resulting from decomposition of naphthalene sullonic acid and distillation of dissolved naphthalene.

13 Resultant concentrated acid water (57.3 pounds)- had the following analysis:

Percent [sf-NSA 42.7 Free S04= as H280., 12.6 Total' acidity as H280, 29.4

This concentration procedureresulted in an 84% actual recovery of -NSA through this step. The concentrate was then drained from the kettle into stainless steel trays and allowed to harden.

B. NEUTRALIZATION AND EVAPORATION Brilliant yellow test paper turned orange. Quantities were' as follows:

y Pounds Charge -NSA in charge 4.26 18% sodium sulfte solution -a 23.1 30% sodium hydroxide solution 1.19

Resultant' mass was dehydrated in this mixer; for a period of nine hours. Dried material amounted to 11.1 pounds. Recovery of -NSA, corrected for handling losses, over this step was 94.0%.

C. FUSION, SPRINGING, FILTRATION, AND DISTILLA- I TION Six pounds of 100% sodium hydroxide was then charged to a 2 gallon, iron, direct tired, agitated fusion pot. Caustic was melted by heating pot to 305 C., 10.69 pounds of` the neutralized mass from the preceding step were then slowly added to the molten caustic at such a rate as to maintain the temperature between 290-310 C. Molar ratio of caustic to NaNS was 8.6; or on the basis of total dry salts as charged, it was 3.23. The fusion mass was then held at 305 C. for 1/2 hour after the addition of salt was completed. The mass (15.87 pounds) was then cooled to room temperature and transferred to a stainless steel tray.

Water (47.6 pounds) and the fusion mass (15.87 pounds) were then charged at a 3:1 lweight ratio to a 10 gallon stainless steel jacketed and agitated kettle. The mixture was then heated to 95 C. with agitation. Sulfur dioxide (4.88 pounds) was then bubbled through the mass from the bottom outlet valve until Brom Thymol Blue test paper remained yellow. The contents (65.1 pounds) were then cooled slowly to room temperature and filtered. Resultant cake (crude -naphthol) was then washed with water; final weight was 6.31 pounds having 51.1% volatiles at 60 C. An aliquot of the lter cake was dried in the laboratory at 60 C. Weight of the dry cake was 3.09 pounds.

The dry cake aliquot was then distilled at reduced pressure ina six-ball Snyder column to obtain residue-freed -naphthol containing 0.75% a-naphthol.

Overall yield of -NSA for the fusion, springing and distillation was 77.3%. This results in a 72.5% yield from the concentrated acid water.

The residue-freed -naphthol `was fractionated at reduced pressure in a 1" x 36" laboratory Stedman column. Refined -naphthol (0.24% a-naphthol) was obtained in 94.1% yield. A further portion of material (2.98% of the charge) contained 17.64% a-naphthol and could have been further processed for that product.

Although certain preferred embodiments of theinvenr. tion have been disclosed for purpose of illustration, it willf be evident that various changes and modifications may be made therein without departing from the scope and spirit.I

of the invention.

I claim:

1. A process for the treatment of crude naphthalene for the production of high purity naphthalene and the conversion of waste products therefrom into substantial.

amounts of maphthol which comprises subjecting crude naphthalene with 10-25 parts by weight of crude naphthalene of concentrated sulfuric acid at a temperature of 15G-170 C. to violent agitation to effect intimate contact between the crude naphthalene and sulfuric acid to form essentially a single phase, i.e. a homegeneous mixture that does not separate into layers, thereafter adding water to the single phase mixture at a temperature of C. to form an acid water aqueous phase containing naphthalene sulfonic acids, impurities and a naphthalene phase, withdrawing the aqueous phase, washing the thus' separated naphthalene phase Awith an aqueous caustic sofl lntion, withdrawing the aqueous caustic solution after contact with the naphthalene, fractionally distilling the; thus treated naphthalene and recovering as distillate a high quality naphthalene, passing steam in direct contact;-

with said acid water at a temperature of -l70 C. to convert naphthalene-l-sulfonic acid contained in the acid water to naphthalene, removing said naphthalene from the acid water, neutralizing the residual acid water con.

taining naphthalene-Z-sulfonic acid to produce sodium.l

naphthalene-Z-sulfonate, fusing the sodium naphthalene- 2-sulfonate with sodium hydroxide to eiect desulfonation' of the sodium naphthalene-Z-sulfonate to sodium -naphtholate, diluting the melt with `water and acidifying the sodium -naphtholate to form -naphthol, and recovering the ,fi-naphthol.

2. A process for the treatment of crude naphthalene;

for the production of high purity naphthalene and the conversion of waste products therefrom into substantial amounts of -naphthol 4which comprises subjecting crude naphthalene with 10-25 parts by weight of crude naphthalene of concentrated sulfuric acid at a temperature of 150-170" C. to violent agitation to effect intimate contact between the crude naphthalene and sulfuric acid to form essentially a single phase, i.e., a homogeneous mixture that does not separate into layers, thereafter adding water to the single phase mixture at a temperatureof 80-100 C. to form an acid Water aqueous phase containing naphthalene sulfonic acids, impurities and a naphthalene phase, withdrawing the aqueous phase, washing the thus separated naphthalene phase With an aqueous caustic solution, withdrawing the aqueous caustic solution after contact with the naphthalene, fractionally distilling the thus treated naphthalene and recovering as distillate a high quality naphthalene, concentrating said acid water by evaporation, passing steam in direct contact with the concentrated acid water at a temperature of 15G-170 C. to convert naphthalene-lasulfonic acid contained in the acid water to naphthalene, removing said naphthalene by vaporization from the acid water, neutralizing the residual waste water containing naphthalene-Z-sulfonic acid with said aqueous caustic solution resulting from washing said naphthalene phase and a mixture of sodium sulfate and sodium suliite to produce sodium naphthalene-2- sulfonate and `sulfur dioxide gas, separating the sulfur dioxide gas from the reaction mixture, fusing said naphthalene-Z-sulfonate with sodium hydroxide at a temperature of about 290-350 C. to effect desulfonation of the sodium naphthalene-Z-sulfonate to sodium -naphtholate, diluting the melt resulting from the fusion with water and acidifying with said sulfur dioxide to convert the sodium -naphtholate to -naphthol which separates as one layer and an aqueous solution of sodium sulfate and sodium sulte, recycling said aqueous solution of sodium sulfate and sodium sulite for neutralizing the naphthalene-Z-sul` -3. A process for the treatmentof crude ynaphthalene for the production of high purity naphthalene and the conversion of waste products therefrom into substantial amounts of -naphthol which comprises subjecting crude naphthalene with 14-20 parts by weight of crude naphthaY 'Iene of concentrated sulfuric acid containing 93-96% H2804l at a temperature of 155-165 C. to violent agitation to effect intimate contact between the crude naphthal Iene and sulfuric acid to form essentially a single phase, i. e., a homogeneous mixture that does not separate into layers, thereafter adding water to the single phase `mixture at a temperature of 85-90" C. to form an acid water aqueous phase containing naphthalene sulfonic acids, impurities and a naphthalene phase, withdrawing the aqueous phase, washing the thus separated naphthalene phase with an aqueous caustic solution, withdrawing the aqueous caustic solution after contact with the naphthalene, fractionally distilling the thus treated naphthalene and recovering as distillate a high quality naphthalene, concentrating said acidV water by evaporation, passing steam in direct contact with the concentrated acid water at a temperature of 15G-170 C. to convert naphthalene-1-sulfonic acid containedin the acid water to naphthalene, removing said napthalene by vaporization from the acid water, neutralizing the residual waste water containing naphthalene-Z-sulfonic acid with -said aqueous caustic solution resulting from 'washing said naphthalene phase and at mixture of sodium sulfate and sodium sulte to produce sodium naphthalene-Z-sulfonate and sulfur dioxide gas, separating the sulfur dioxide gas from the reaction mixture, fusing said naphthalene-2sulfonate with sodium hydroxide at a temperature of about 290-350" C. to effect desulfonation of the sodium naphthalene-2sulfonate to sodium [fl-naphtholate, diluting the melt resulting from the fusion with Water and acidifyingwith said sulfur dioxide to convert the sodium -naphtholate to -,naphthol which separates as one layer and an aqueous solution of sodium weight of crude naphthalene of concentrated sulfuric acid at a temperature of 150-170"` C. to violent agitation to'- sulfateand sodium sulte, recycling said aqueous solution of sodium sulfate and sodium sulte for neutralizing the naphthalene-Z-sulfonic acid to produce the sodium naphthalene -2-sulfonate, and recoveringrsaid -naphthol.

4. A process for the treatment ofv'crude naphtl-lalene for the production of high purity naphthalene which comprises subjecting crude naphthalene` with 10-25 parts by effect intimate contact between the crude naphthalene and sulfuric acid to `form essentially a single phase, i.e. a homogeneous mixture that does not separate into layers, thereafter adding water to the single phase mixture at a temperature of -100 C. to form an acidwater aqueous' phase containing naphthalene sulfonic acids, impurities anda naphthalene phase, withdrawing theaqueous phase, washing the thus separated naphthalene phase with an aqueous caustic solution, withdrawing the aqueous caustic solution after contact with the naphthalene, and fractionally distilling the thus treated naphthalene, and recovering as distillate a `high quality naphthalene.

5. A process for the treatment of crude naphthalene for the production of high purity naphthalene which comprises subjecting crude naphthalene with 14-20 parts by weight of crudeinaphthalenefof concentrated sulfuric acid containing 93-96% H2804 at a temperature of 15S-165 C. to violent agitation to effect intimate contact between the crude naphthalene and sulfuric acid to form essentially a single phase, i.e. a homogeneous mixture that does not separate into layers, thereafter adding water to the single phase mixture at a temperature of -95 C. to form an acid water aqueous phase containing naphthalene suli fonic acids, impurities and a naphthalene phase, withdrawing the aqueous phase, washing the thus separated naphthalene phase with Van aqueous caustic solution, withdrawing the aqueous caustic solution aftercontact with `the naphthalene,' and fractionally distilling the thus treated naphthalene and recovering as distillate a high quality naphthalene.

References Cited inthe ile of this patent UNITED STATES PATENTS Schoeifel et al. Aug. 28, 1956' 

1. A PROCESS FOR THE TREATMENT OF CRUDE NAPHTHALENE FOR THE PRODUCTION OF HIGH PURITY NAPHTHALENE AND THE CONVERSION OF WASTE PRODUCTS THEREFROM INTO SUBSTANTIAL AMOUNTS OF B-NAPHTHOL WHICH COMPRISES SUBJECTING CRUDE NAPHTHALENE WITH 10-25 PARTS BY WEIGHT OF CRUDE NAPHTHALENE OF CONCENTRATED SULFURIC ACID AT A TEMPERATURE OF 150-170*C. TO VOILENT AGITATION TO EFFECT INTIMATE CONTACT BETWEEN THE CRUDE NAPHTHALENE AND SULFURIC ACID TO FORM ESSENTIALLY A SINGLE PHASE, I.E. A HOMEGENIOUS MIXTURE THAT DOES NOT SEPARATED INTO LAYERS, THEREAFTER ADDING WATER TO THE SINGLE PHASE MIXTURE AT A TEMPERATURE OF 80100*C. TO FORM AN ACID WATER AQUEOUS PHASE CONTAINING NAPHTHALENE SULFONIC ACIDS, IMPURITIES AND A NAPHTHALENE PHASE, WITHDRAWING THE AQUEOUS PHASE, WASHING THE THUS SEPARATED NAPHTHALENE PHASE WITH AN AQUEOUS CAUSTIC SOLUTION, WITHDRAWING THE AQUEOUS CAUSTIC SOLUTION AFTER CONTACT WITH THE NAPHTHALENE, FRACTIONALLY DISTILLING THE THUS TREATED NAPHTHALENE AND RECOVERING AS DISTILLATE A HIGH QUALITY NAPHTHALENE, PASSING STEAM IN DIRECT CONTACT WITH SAID ACID WATER AT A TEMPERATURE OF 150-170*C. TO CONVERT NAPHTHALENE-1-SULFONIC ACID CONTAINED IN THE ACID WATER TO NAPHTHALENE, REMOVING SAID NAPHTHALENE FROM THE ACID WATER, NEUTRALIZING THE RESIDUAL ACID WATER CONTAINING NAPHATHLENE-2-SULFONIC ACID TO PRODUCE SODIUM NAPHTHALENE-2-SULFONATE, FUSING THE SODIUM NAPHTHALENE2-SULFONATE WITH SODIUM HYDROXIDE TO EFFECT DESULFONATION OF THE SODIUM NAPHTHALENE-2-SULFONATE TO SODIUM B-NAPHTHOLATE, DILUTING THE MELT WITH WATER AND ACIDIFYING THE SODIUM B-NAPHTHOLATE TO FORM B-NAPHTHOL, AND RECOVERING THE B-NAPHTHOL. 